Download Sponge Bob dihybrid

Bikini Bottom – Dihybrid Practice
Name ________________________
Use the chart to identify the genotypes of the
following traits:
1. Heterozygous round eyes, blue body ________
2. Hybrid eye shape, purebred roundpants ________
Trait
Body Shape
Body Color
Eye Shape
Nose Style
Dominant Gene
Squarepants (S)
Yellow (Y)
Round (R)
Long (L)
Recessive Gene
Roundpants (s)
Blue (y)
Oval (r)
Stubby (l)
3. Purebred roundpants, heterozygous long nose ________
SpongeBob’s aunt, who is a roundpants, has a cute stubby nose. She has finally found the sponge of her
dreams and is ready to settle down. Her fiancé always comments on how adorable her nose is (he says it
reminds him of his mother’s – aww, how sweet!). They wonder what the chances are of that trait being
passed on. Her fiancé is a purebred squarepants and has purebred long nose.
4. Identify the genotypes of the aunt and her fiancé.
Aunt – Roundpants, Stubby Nose = ________
Fiancé – Purebred Squarepants, Long Nose = ________
5. What are the possible gamete combinations for each person? Aunt – ________ Fiancé – ________
6. What are the possible genotypes for their children? ______________________________________
7. What are the genotypes of SpongeBob, who is heterozygous for his yellow body color and his
squarepants, and his wife SpongeSusie, who is blue and has roundpants?
SpongeBob = ________
SpongeSusie = ________
8. What are the possible gamete combinations for each person?
SpongeBob = ________________
SpongeSusie = ________
9. Complete the Punnett square based on the information provided in #7-8 and then answer the questions.
What is the chance of a blue baby? ________
What is the chance of a squarepants? ________
What is the chance of a blue squarepants? ________
What is the chance of a purebred recessive for both traits? ________
Contributed by Andrea Stonebraker
http://sciencespot.net/
10. In starfish, pink body color (P) is dominant to orange (p), and thick eyebrows (T) are dominant over
thin (t) ones. Patrick, who is heterozygous for body color but purebred for thick eyebrows, has met Patti,
who is recessive for both traits.
What is Patti’s phenotype? _______________________________
Is it possible for the new couple to have offspring that resemble their mother? Explain.
______________________________________________________________________________
______________________________________________________________________________
11. Before Patrick commits to this relationship, he would like to guarantee that his offspring would have
his thick eyebrows. (He thinks they make him smarter!) You need to provide evidence for or against the
marriage. This question regards eyebrows ONLY.
12. While Squidward’s family boasts about being a purebred line for dominant
light blue skin color, they are also purebred for a less distinguished trait: the
recessive trait of baldness. Lack of hair causes Squidward some self-esteem
issues that he does not want his children to face. He would like to ensure that his
offspring have hair AND with his blue skin color. What traits should he look for
in a bride?
Squidward Traits:
Skin Color
Blue = B, Green = b
Hair
Hair = H, Bald = h
Must she have hair? Explain. ____________________________________________________
___________________________________________________________________________
Must she be blue? Explain. ____________________________________________________
___________________________________________________________________________
13. Squidward has found a potential bride prospect with the green squid Octavia. While Octavia has hair,
her father does not. Determine the chances of their child being blue and having hair.
Squidward = ________
Octavia = ________
14. Use the genotypes in #13 to complete the Punnett square below and then answer the questions.
For which traits, if any, is it possible for their offspring to be purebred?
What is the probability of their children being heterozygous for both traits? ________
Contributed by Andrea Stonebraker
http://sciencespot.net/